Figure 4 Hierarchical clustering analysis for the protein expression profiles in P. massoniana seedlings cultivated at various Ca levels . Fold changes of protein abundance under low or high Ca levels compared with the control (medium Ca level) were log2 transformed and delivered to Cluster and Treeview software. The protein cluster is on the left side and the treatment cluster is on the top. The rows represent each differentially expressed protein. The proteins with increased abundance or decreased abundance are indicated in yellow or blue, respectively. The color intensity was shown in the bar at the right bottom corner of the figure.